Compressor system



Oct. 28, 1941. H. F. PARKER r 2,260,538

COMPRESSOR SYSTEM Filed May 21, 1938 2 Sheets-Sheet l [N VEN TOR 46 p/m Fpbrker BY E =M,2M ina ATTORNEY-5.

Oct. 28, 1941. H. F. PARKER 2,260,538

9 COMPRESSOR SYSTEM Filed May 21, 195s 2 Sheets-Sheet 2 IQNVENTOR 7 Humphrey E Par/re) ATTORNEYS- Patented Oct. 28, 1941 I Humphrey F. Parker, Detroit, Mich. Application May 21, 1938, Serial No. 209,181

' 2 Claims.

The present invention relates to compressor systems, and in particular provides an improved compressor system for supplying air or other fluid under pressure for the operation of brakes, door openers, or the like on automotive vehicles such as buses and trucks.

The principal objects of the present invention are to provide a system of the above generally indicated character, which is adapted to remove from the delivered air or other fluid the nongaseous impurities such as excess lubricating oil and solid or liquid decomposition products thereof, thereby freeing the collecting reservoirs of objectionable accumulations of such matter and preventing deposits thereof on valves and other parts of the operating mechanism; to provide a system which makes practicable the use of simpler types of compressors, such as the rotary type, than have heretofore been found to be practicable; andto provide such a system which reduces the delivery temperature of the, airor other compressed fluid, by introducing into the air or other fluid a quantity of oil or the like which absorbs a portion of the heat of compression.

Further objects of the present invention are to provide a system of the above generally indicated type, characterized in thatoil for lubricating and for sealing the clearance spaces in the compres- Figure 5 is a view in vertical longitudinal section, taken along the line 5-5 of Figure 2;

Figure 6 is a view in horizontal section, taken along the line 8-6 of Figure 3; v

Figure '7 is a view in vertical transverse section, taken along the line l-l of Figure 2; Figure 8 is a view in vertical section, taken along the line 8-8 of Figure 3; and

Figure 9 is a fragmentary view of a modified embodiment of the invention. It will be appreciated-from a complete understanding of the invention that the improvements thereof may be embodied in compressor systems Y of widely differing types, and adapted for widely differing applications. In the specific forms illustrated, however, the improvements of the invention are particularly adapted for use in consor is supplied thereto from the lubricating system of the associated vehicle engine: to provide I such a system in which the excess of the oil supplied to the compressor is returned therefrom to the vehicle oiling system; to provide such a system in which means are provided to separate the oil from the compressed fluid and in which the separated oil is returned to the supply system; to provide such a system including means to return to the engine lubricating system all but a predetermined quantity of the oil supplied to the compressor, thereby insuring the maintenance of a proper oil supply in the engine system;

and to provide such a system embodying improvements in the construction andarrangement of the parts thereof.

With the above as well as other objects in view, which appear in the following description and in the appended claims, preferred but illustrative embodiments of the invention are shown in the accompanying drawings, throughout the several views of which corresponding reference characters are used to designate corresponding parts and in which:

Figure 1 is a general view in elevation, partly in section, of a preferred embodiment of the. invention;

Figure 2 is a view in bottom plan of the improved compressor of the present invention;

means of a oil pump for relief valve mechanism nection with automotive vehicle compressor systems, it being understood that in such systems the compressed air or other fluid may be utilized to operate the brakes, doors, and other mechanism associated with the vehicle; I 1

Referring to the'drawlngs, the improved compressor B0 of the present invention is supported at the side of an internal combustion engine I! by means of the bracket 14. The compressor i0 is believed to be of itself of novel form and is of i the gear type.

It will be understood, however, that in its broader aspects, the invention is applicable to other forms of compressors, suchas radial vane compressors and also such as reciproeating compressors. It will be appreciated that in the use of rotary compressors of the illustrated gear type, it is desirable to supply oil thereto both for the purpose of lubricating the compressor bearings and for the purpose of sealing the clearance spaces around the gear teeth, to prevent leakage losses'which would otherwise occur due to normal manufacturing tolerances. The arrangment of the present invention is such that oil is supplied to the compressor In by the engine both of the just mentioned purposes.

The shaft iii of the compressor I0 is driven, through the flexible coupling l8, from any suitable moving part of theeusine, such as the shaft of the generator (not shown). In a broader sense, it will be appreciated that the compressor may be driven in any other suitable way, such as by belt and pulley. It is preferred that arranged for continuous driving engine is dispensing with clutches, but

the compressor Ill be in operation, thus making advisable which is described below.

The lubricating oil pump 20 of. engine I! is driven from the engine crankshaft 22 by means Figure 3 is a view in vertical longitudinal section, taken along the line 3-3 ofFigure 2;

Figure 4 is a view in vertical transverse section, taken along the line 44 of Figure 2;

of the usual helical gears 24' and 26. Oil is taken from the engine sump 28 through the inlet 30 of pump 20, and is delivered under pressure'thereby to the pump outlet 32. Passage N communicates directly with theoutlet l2. and transmits the oil the provision of unloader or.

turnings.

to a longitudinal header 88,*from whence it is distributed to the main bearings and other parts of the engine to be lubricated. The header 36 is tapped into by a compressor oilline 38, the other end whereofis suitably'connected into the compressor inlet 48, as most clearly appears in Figures 1 and 4. Preferably and as illustrated, the compressor inlet 40 is provided with a metering orifice 42, which serves to limit the'amount of the oil delivered to the compressor to a suitable quantity.

The quantity of oil delivered to the compressor l through the metering orifice 42 is preferably considerably in excess of that required for lubri- I cation, and may, for. example, be of .such an order that the weight of the delivered oil equals or somewhat exceeds 'the weight of the air or other fluid takenv into the compressor. .The excess of such oil, over and above what is required.

for lubricatingpurposes, is utilized in the practiceof the present invention for the purpose of sealingv the clearance spaces within the compressor and also for suitably reducing the temperature of the compressed air or other fluid. As is described more in detail hereinafter, the just mentioned excess oil is separated from the compressed airor other fluid and all such oil in excess of a predetermined quantity is returned to the supply system.

Referring further to the drawings and parfrom sump 62 in communication" with an outlet. port 18.. The outlet port 18 leads through the.

oil return pipes 88- and '82 back to the engine sump. I

- It will be noted'thatfthe returnpipe 82 is pro' I vided with an additional branch 84 whichis connected into a short passage 85 which in turn.

opens into the bottom of the compressor air intake 52 (Figure 4). The purpose of this branch connection is topermit a direct return of the-oil to the engine sump in the event of the stoppage of the compressor while the engine i2 is in operation. While this eventuality isflvery remote, it is preferred that. it be provided for in certain cases, forexample when the drive is by means of a belt and pulley. The branch line 84 remains open during the time that the compressor I0 is in operation. 1 During such operation, however, the great majority of the oil delivered from the metering orifice 42 directly impinges upon the gear teeth and is thereby carried around into the ticularly to Figures 3 and 4, oil delivered through the metering orifice 42 strikes the teeth of the gears '44 and 46, and is carried around in the 4 spacesbetween the gear teeth, along with air inducted through a usual air filter-48, air line 58, and compressor air inlet 52. The air iscompressed by the action of the gears 44 and 46 in awell known manner, and is discharged, along with the entrained oil,- through an outlet'54, which as most clearly appearsin Figures 3 and '7, opens directly into a separating chamber 56.

The separating chamber 56, which is formed integrally with the gear chamber, is of relatively large area, and is filled or substantially filled, with a material such as'steel or copper wool.

' As shown, the separator '56 is providedlwith suitablebaiiles 58 and 80 to cause the air to follow a tortuous path therethrough, as is generally indicated by the arrows in Figure 6, from the inlet 54,around the baflles 58 and 80. Due to their inertia; the liquid oil particles adhere to and collect upon the surface of the steel or copper The oil film thus deposited gradually forms into drops which are too heavy to be carried forward by the low velocity air stream, and such drops, accordingly, fall by gravity and are collected within' a sump 62.1'ormed at the bottom of the separator 58. The air, thus freed 7 of its entrained oil, passes out of the separator and 65 past a spring loaded non-return valve 66' into a chamber space 68. 'As clearly appears in compressor as described above.

As previously mentioned, it is preferred to provide the compressor with suitable unloader or relief valve mechanism. Referring particularlyto Figure -5, a passage 86 leads to the bottom of the previously mentioned chamber space 68 into a chamber space 88, which is thus subject to the fluid pressure in the space 68 and in the delivery line 12. The just mentioned pressure'within the chamber 88 acts upon a metal bellows 98, and is resisted by a spring 92 and the air pressure acting upon a valve 94, the push rod 95 whereof rests against the inner member 91 forming the closed end of the bellows 98. When the pressure upon the bellows exceeds the just mentioned opposing forces, the valve 94 is forced open, permitting air to escape fromthe separator 56, and thence through the passage 63 and 96 directlyinto the.

compressor air inlet 52. The return valve 66, however, which is maintained in its closed position under the just mentioned conditions by its associated spring 6], serves to prevent a flow'of air from the storage reservoir and line I2 through the relief passage 96.- In'conseq'uence, a high pressure is maintained in the storage reservoir although the delivery side of the compressor and separator are substantially relieved of pressure; Continued operation of the compressor causes the usual circulation of air therethrough, but because of the absence of back pressure, the engine 1s relieved of the load of compression.

It will be noted that once the valve 94 is forced open, it is relieved of the pressure onits upper face, so that the pressure on the metal bellows 90 exceeds the resistance of the'spring 92 by'a considerable margin. When the pressure within the reservoirfalls, due for example to the application -of the brakes or other equipment to be operated thereby, the pressure on the bellows is reduced below such margin, rendering the bellows 98 unable to balance the resistance of the spring Figure 6, the chamber space I 68 communicates .directly with the compressor delivery pipe 12.

lifts valve 18, which places a passage 'l'l leading 92. Valve 94. thereupon moves to the closed position, and pressure is again built up upon the delivery side of the compressor until such pressure equals that on the reservoir side of check valve 66, at which time valve 66 again opens permitting the delivery of the compressed air to the storage reservoir.

It will be noted that the compressor I8 is illustrated as comprising two companion sets of gears 44 and 46 and 98 and I00. The provision of these two sets of gears provides two stages of compression, whereby losses in'volumetric efllciency due to clearance spaces between the gear I01. -ciat'ed with the first pair of gears M and through the inlet II, is carried around by these gears and passes into the'space lllbetween the two partitions through an opening llll formed in the partition I05. The air passes along the Just mentioned space, to the inlet side of the compressor, and is 'admitted to the inlet side of the gears 88 and Ill) through an opening iii! formed in the partition lll. After being carried 15 around in the spaces between the teeth of the gears 98 and Hill, the air passes into the separator-J6, through the previously mentioned outlet 34, which is formed in the inner wall of the gear housing. It will be appreciated that the oil degears M and 48, thereby sealing the clearance spaces therebetween; in part is carried aroundv by the air and adheres to the teeth of the gears to and llll, thus correspondingly sealing the clearance spaces therebetween; and in part is carried by the air into the separatingchamber It. following which it is recollected in the pre'-.

I 80. In the present instance, the lubrication of the viously described manner.

compressor bearings "M, ill, I", and III is 4 adequately taken care, of by oil from the'fllm which occupies the clearance spaces between the ends of the gears and the casing. It wili be understood, of course, that in the broader aspects of the invention, full engine oil pressure may be supplied to the just mentioned bearings by providing a suitable passage leading from the oil.

intake 4..

It will be appreciated that a substantial part of the heat of compression is transferred to the *oil which is entrained with the air being compressed, so that the air is delivered to the storage rearvoir (not shown) at a substantially lower as the invention have'been disclosed in detail, it.

temperature than would'otherwise be the-case. As will be further understood, the actual de ree to which the temperature of the air is reduced, depends upon the relative weights of the air and theoil.

The absorption by the oil of part of the heat of compression of the air necessarily. raises thetemperature of this oil to a value'higher than the temperature at which the oil may be exso fluid line for delivering oil from said reservoir to said compressor, means for controlling the pected to enter the compressor inlet ll. However, in the embodiment described above, the recollected oil, in excess of a predetermined quantity thereof, is returned directly from the sump 62 to the engine sump, which lattersump. is occupied .by. a relatively large body of oiland may be expected to be maintained at a temperature substantially lower than the initial ternperature of the recollecte'd oil. Accordingly. the present arrangement provides for the cooling of the recollected oil before it is again circulated through the compressor.

In certain instances, where the just mentioned cooling effect is not-of substantial importance,-

it has been found that an economy in theamountt of oil lines required may be effected by the arrangement shown in Figure 9, in which only a single oil line is required between the engine and the compressor. a

In m. o, the oil is delivered .as in the p e- 7sample, of about 30 pounds per square inch,

a0 iivered into the compressor through the metering nomle 42, in part adheres to the teeth of the 60 What is claimed is:-

.- viously described embodiment to the compressor from the vehicle oil' pump 20, through the line 3.8a and the compressor oil inlet "a. In this instance, however, the compressor oil outlet Ila, instead of being connected to a line leading to the oil engine pump, is connected to a line 2 which is tapped into the supply'line 38a.

It will be appreciated that the oil pressure within the line 38a, as developed by the pump 20, is of a moderate value of the order, for exwhereas the pressure existing within the compressor separator, may be expected, to be of the order 100 pounds per square inch. when the float controlled valve associated with the compressor separator opens, the oil inthe bottom of the separator pump is discharged into the line H: at thejust mentioned relatively high 'separator pressure, against the relatively low supditions, accordingly,. the oil discharged through the oiloutlet 18a re-circulates' directly intothe compressor oil inlet 40a. Any-tendency towards a reduction in the normal quantity of .oil'inthe local circuit including the line 2 and the, compressor 10 is met by an additional supply of oil from the pump 20 through the line Ila, thus bringing the quantity to thenormal expected value. On the other hand, any tendency for the quantity of oil in the just mentioned local circult to exceed a predetermined normal; is overcome by the ability of the superior pressure in line 2 to force oilback through the line "a into the engine header 36, it being understood, of, course, that the back pressure at the compress'or inlet metering orifice is substantially equal to the pressure developed by the pump 20.

Except in the respect noted above, the embodiment of Figure 9 may and preferably does correspond in all respects to the embodiment shown in Figures-1' "through 8, and this relationis indicatedby the use of corresponding reference characters, with the subscript a,

Although only two specific embodiments of will be appreciated that various other modifications maybe made in the form, number and- H arrangement of the parts within thespirit" and scope of the invention.

v 1. The combination of an engine. a comj pressor associated with said engine, 'an oil reservoir in said engine constituting a source of lubricant therefor, means including a pump and, a

quantity of the oil so delivered, and means asso! ciated with said compressor for separating the oil entrained with the compressed fluid from said 90 fluid at a pressure in excess of that developed,

by said pump and for returning'oil in excess of a predetermined quantity from said last nam means to said fluid line. a Y 2. The combination of an enginehaving a rog tatingpart, a rotary compressor driven from said part, a lubricating system for said engine,'

70-011 entrained with the compressed fluid fromsaid iluid at a pressure above atmospheric. and

means for returning said separated oil to said engine lubricating system.

ply pressure in the line 38a. Undernormal con- 

